1. Field of the Invention
The present invention relates to a tripod attachment through which a pair of binoculars is mounted on a tripod.
2. Description of the Related Art
Japanese Utility Model No. 3064125 discloses a tripod attachment for a pair of binoculars, which comprises an attachment body, a collet chuck, and a chuck lever. The collet chuck is inserted into a tapered hole of the attachment body, and the chuck lever is connected with the collet chuck. The pair of binoculars comprises two small telescopes fitted together side by side through a pair of bridges with a pivot. In order to attach the pair of binoculars to the tripod attachment, a bolt protruding from the pivot is inserted into the collet chuck, and the collet chuck is then pulled into the tapered hole by fastening the chuck lever. By this operation, jaw members of the collet chuck are closed so as to press and hold the bolt with the jaw members, and the pair of binoculars is thus attached to the attachment body through the collet chuck.
In order to practically use the pair of binoculars, an interval between eyepieces of the two telescopes must be adjusted to the interval between the eyes of the user by revolving the two telescopes on the pivot with respect to each other (this adjustment is hereinafter referred to as eyepiece-interval adjustment). One of the telescopes is connected with the bridge on which the pivot is rigidly attached, and the other of the telescopes is connected with the other bridge that is rotatably connected on the pivot. Hence, even though the pair of binoculars is mounted on the tripod through the tripod attachment so as to make the two telescopes horizontally arranged before the eyepiece-interval adjustment, the two telescopes become not horizontally arranged after the eyepiece-interval adjustment, since only one of the telescopes is revolved on the pivot; consequently, right and left fields of views are inclined from the horizontal. Then, the inclination of the pair of binoculars should be corrected by rotating the entire pair of binoculars around the pivot so that the two telescopes are horizontally arranged (this correction is hereinafter referred to as horizontal correction).
In order to solve that problem with the conventional tripod attachment, the chuck lever is loosened after the eyepiece-interval adjustment, and the pair of binoculars is rotated to make the two telescopes horizontally arranged to correct the inclination of the fields of views, then the chuck lever is fastened again.
The conventional tripod attachment thus requires operations for loosening and fastening the chuck lever in order to perform the horizontal correction after the eyepiece-interval adjustment, and handling such a tripod attachment is bothering.
Moreover, since the conventional tripod attachment has a short coupling part for coupling the collet chuck and the bolt on the hinge joint of the pair of binoculars, the bolt sometimes accidentally falls from the collet chuck.
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of a tripod attachment that enables an easy horizontal adjustment and enables easy handling.
In order to achieve the above-described objects, the present invention is directed to a tripod attachment for attaching a pair of binoculars having a pivot to a tripod, the tripod attachment comprising: an attachment body which is attached to the tripod, the attachment body having a hole; a shaft member which is rotatably inserted through the hole of the attachment body, an end of the shaft member being fastened to the pivot of the pair of binoculars; and a friction force producing member which is arranged at the attachment body, the friction force producing member producing friction force when fastening the shaft member to the pivot, the friction force holding the pair of binoculars at any desired position with respect to the attachment body, the friction force allowing the pair of binoculars to rotate around the shaft member only when certain external force is applied to the pair of binoculars.
According to the present invention, the attachment body is attached to the tripod, and the shaft member is rotatably inserted through the hole of the attachment body and fastened to the pivot, whereby the pair of binoculars is attached to the tripod through the tripod attachment. Then, one of two telescopes constructing the pair of binoculars is revolved on the pivot so as to adjust the interval between the eyepieces, and the entire pair of binoculars is rotated around the shaft member against the friction force produced by the friction force producing member. After that, when application of rotating force to the pair of binoculars is stopped at a position where the two telescopes are horizontally arranged, the pair of binoculars is held at the position by the friction force produced by the friction producing member. Therefore, the tripod attachment of the present invention can be easily handled since it enables the horizontal correction without loosening and fastening the shaft member.
Preferably, the pivot of the pair of binoculars has a threaded hole; the shaft member has a threaded portion on the end thereof; and the shaft member is fastened to the pivot by screwing the threaded portion in the threaded hole.
According to the present invention, the pair of binoculars is not accidentally detached from the tripod attachment, since a fastening structure is used as the attaching structure between the tripod attachment and the pair of binoculars with which the screw member is fastened to the pivot.
According to an embodiment of the present invention, the friction force producing member comprises a sleeve which is inserted in the hole of the attachment body, the shaft member being inserted through the sleeve, the sleeve comprising: an extending part which is extended when the shaft member is inserted in the sleeve; and an engaging part which engages with the pivot of the pair of binoculars so that the sleeve is rotated when the pivot rotates, wherein the friction force is produced between the extending part being extended and the hole of the attachment body.
According to another embodiment of the present invention, the friction force producing member comprises: an annular body through which the shaft member is inserted, the annular body having an engaging part which engages with the pivot of the pair of binoculars so that the annular body is rotated when the pivot rotates; and a pressing member arranged between the annular body and the attachment body, the pressing member pressing the annular body toward the pivot, wherein the friction force is produced between the annular body and the pressing member.